JPS5929751A - Fuel change-over unit in gasoline-kerosene change-over type carburetor - Google Patents

Abstract

PURPOSE:To obtain a compact carburetor in a compound fuel engine whose main fuel is kerosene by using a fuel passage from a change-over valve to a gasoline chamber as that for both gasoline and kerosene concurrently and by supplying only gasoline to the engine until its warming up is completed. CONSTITUTION:A change-over valve 17 is provided with the first valve seat 22 connected to a kerosene supplying passage 26 extending from a kerosene tank 28, the second valve seat 24 connected to a gasoline supplying passage 27 extending from a gasoline tank 29, and a kerosene-valve-body 21 and a gasoline- valve-body 23 which alternately open/close those valve seats 22 and 24 facing each other on straight line. The outlet 25 of the changeover valve 17 is connected to the inlet 8 of a fuel passage 5. The negative pressure chamber 30 of this change-over valve 17 is connected to the downstream side from a throttle valve via a negative pressure passage 12 that is provided with a temperature- operate dvalve 13. When the engine is not sufficiently warmed up, the temperature-operated valve 13 keeps its negative pressure passage 12 closed so that air-intake tube negative pressure dose not act upon the negative pressure chamber 30, permitting continuation of gasoline supply.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel switching device for a single-boat chamber type carburetor used in an equal pressure engine for agricultural machinery using kerosene as the main fuel.

As is well known, engines that use kerosene as fuel usually use gasoline at the time of starting to make it easier to start. Either a single-float chamber type carburetor or a single-float chamber type vaporizer in which a gasoline chamber is provided inside the float chamber are used. Among these, the former is complicated in structure and large in size, so the latter is mainly used. A single-roat chamber type carburetor injects gasoline into the gasoline chamber provided at the south lower part of the float when starting the engine, and uses this gasoline to start the engine, but when the gasoline in the gasoline chamber is consumed, the engine warms up. It automatically switches to kerosene regardless of the engine temperature, so if the switch is switched to kerosene before the engine temperature reaches full temperature, the engine may stop.
In such cases, it was necessary to refill the engine with gasoline and start it again. In order to solve this problem, it is possible to make the gasoline chamber larger and increase the amount of gasoline injected, but this method either increases the size of the entire carburetor or requires a separate gasoline chamber. Furthermore, even after warming up, gasoline is sent to the engine, wasting fuel.

The present invention was invented for the purpose of providing a fuel switching device that can supply kerosene at an appropriate time according to the temperature of the engine without increasing the size of the carburetor.

In order to achieve the above object, the present invention includes a gasoline supply passage, a kerosene supply passage, a switching valve that operates according to the engine temperature, and a fuel passage that can be used for both gasoline and kerosene, and the switching valve is configured to control the two supply channels. Either one of the passages is configured to be connected to the fuel passage, and the fuel passage opens into a gasoline chamber provided at the bottom of the float chamber, and a float valve is provided in the fuel passage. The present invention provides a fuel switching device for a carburetor.

Embodiments of the present invention will be described below with reference to the drawings. Reference numeral 1 indicates a main body of a carburetor having an intake passage 2 extending in the horizontal direction, 3 indicates a float chamber installed below the main body of the carburetor, and 4 indicates an inverter provided at the bottom of the float chamber 3. A bowl-shaped gasoline chamber; 5 is a fuel passage for both gasoline and kerosene that opens from the carburetor body 1 through the side wall of the float chamber 3 to the gasoline chamber 4; 7 is operated by a float 6 to open and close the fuel passage 5; The float valve switching valve 17 has a first valve seat 22 connected to a kerosene supply passage extending from a kerosene tank 4, a second valve seat 22 connected to a gasoline supply passage I extending from a gasoline tank 29, and a second valve seat 22 connected to a kerosene supply passage I extending from a gasoline tank 29. Two valve seats are arranged facing each other in a straight line.

The two valve bodies 21. Z3 is provided on the valve shaft 20 fixed to the center of the diaphragm 18, and the kerosene valve body 21 is seated on the first valve seat 22 by the force of the spring 19 inserted into the negative pressure chamber side partitioned by the diaphragm 18. I'm starting to do that.

Further, the outlet 5 of this switching valve 17 is connected to the inlet 8 of a fuel passage 50. The negative pressure chamber I of this switching valve 17 is connected to the downstream side of the throttle valve through a negative pressure passage 12, and a temperature switching valve 13 is provided in the negative pressure passage 12.

The temperature opening/closing valve 13 opens and closes the negative pressure passage 12 that causes the engine's intake negative pressure to act on the negative pressure chamber recess, and is attached to the engine body 31 so as to directly sense the engine temperature, and has one end fixed. A valve body 15 attached to the free end of a built-in bimetal 14 opens and closes the negative repair passage 12 according to the engine temperature. Generally, the bimetal 14 is set to open when the engine temperature is about 70C or higher.
In addition, the temperature opening/closing valve 13 of the negative pressure passage 12 and the negative pressure chamber (9
) is provided with a check valve 16 that opens toward the temperature shut-off valve 13.

When the engine is stopped, the kerosene valve element 21 is seated on the first valve seat n by the action of the spring 19 of the switching valve 17 to block the kerosene supply passage 26, and the gasoline valve element is moved away from the second valve seat 24. The gasoline supply passage 27 is in an open state. When starting the engine, the trigger 9 is pushed down to allow gasoline to flow from the gasoline supply passage 27, through the switching valve 17 and the float valve 7, through the fuel passage 5, and into the gasoline chamber 4.

After the engine starts, Ganlin is the main Geno in the center) 10
It reaches the main nozzle 11 and is sucked out from the intake passage 2.

When the engine is not sufficiently warmed up, the temperature opening/closing valve 13 closes the negative pressure passage 12 and the suction negative pressure generated downstream of the intake passage 20 throttle valve does not act on the negative pressure chamber 30. Therefore, gasoline is continuously supplied. When the engine warms up to the set temperature, the bimetal 14 bends and the negative pressure passage 1
2 is opened, suction negative pressure is introduced into the negative pressure chamber through the check valve 16 and suctioned against the diaphragm 18 against the elasticity of the spring 19, thereby causing the gasoline valve body to move to the second valve seat 24. The kerosene valve body 2 is seated and at the same time closes the Ganrin supply passage 27.
1 separates from the first valve seat 22 and connects the kerosene supply passage 26 with the fuel passage 5, thereby causing the valve to close. When the pressure and the engine finish warming up in this manner, the switch is made from gasoline to kerosene, but thereafter kerosene is supplied to the float chamber 3 and operation is performed using kerosene.

In the above embodiment, a V-shaped bimetal was used to sense the engine temperature, but a temperature sensor was used instead, and a solenoid valve was used as the switching valve 17, and the switch was electrically connected to the temperature sensor. A valve may be activated.

As described above, the present invention includes a gasoline supply passage, a kerosene supply passage, a switching valve that operates depending on the engine temperature,
The switching valve is configured to connect either one of the two supply passages to the fuel passage, and the fuel passage is connected to a gasoline chamber provided at the bottom of the float chamber. It has an opening and is opened and closed by a float valve, and has a diameter of 4 degrees, so it can be used for conventional kerosene and oil.
Unlike the Solin switching type carburetor, which does not switch from gasoline to kerosene regardless of the engine temperature, it switches at the appropriate time depending on the engine's temperature 3. Therefore, when starting the engine, the gasoline valve body is closed. This eliminates the inconvenience of causing the engine to stop, or conversely, even when the warm-up is completed tλ, the horn solin is supplied and wasted. Also, the fuel passage from the switching valve to the gasoline chamber is used for both gasoline and kerosene, and gasoline is supplied until warm-up is completed, so the purpose can be achieved with a small-volume gasoline chamber, and there is no need to provide a separate gasoline chamber. This has the effect of not increasing the size of the entire vaporizer.

[Brief explanation of drawings]

The drawings are longitudinal sectional views showing embodiments of the present invention. 1... Carburetor main body, 2... Intake path, 3... Float chamber, 4... Gasoline chamber, 5... Fuel passage,
13...Temperature opening/closing valve, 17...Switching valve, 21.
... Valve body for kerosene, 22... Valve body for gasoline. Agent Mutsuaki Nozawa

Claims (1)

[Claims] It comprises a gasoline supply passage, a kerosene supply passage, a switching valve that operates according to engine temperature, and a fuel passage for both gasoline and kerosene, and the switching valve connects one of the two supply passages to the fuel passage. A gasoline-kerosene switching type carburetor, characterized in that the fuel passage is configured to open to a gasoline chamber provided at the bottom of the float chamber, and to be opened and closed by a float valve. Fuel switching device.